A known cyclonic separator is described in US 2012/0000864. The cyclonic separator has an inlet fluidically connected to a fuel tank, a water outlet fluidically connected to an engine fuel feed system, and a fuel outlet. The cyclonic separator is adapted to discharge relatively denser material (including water) from the water outlet and relatively less dense material from the fuel outlet.
A problem with such a known cyclonic separator is that although the overall cyclonic action spins the water out to the separator wall, the fluid dynamic may shear the water off the wall and entrain it back into the bulk fluid due to turbulence, degrading the efficiency of separation.
“Unimpeded Permeation of Water Through Helium-Leak-Tight Graphene-Based Membranes”, R. R Nair et al, Science, 27 Jan. 2012, Vol. 335, no. 6067, pp. 442-444, DOI:10.1126/science.1211694 (referred to below as “Nair et al”) demonstrated that submicrometer-thick membranes made from graphene oxide can be completely impermeable to liquids, vapors, and gases, including helium, but these membranes allow unimpeded permeation of water.
WO2014/174247 describes a tank assembly with a tank for storing liquid hydrocarbon, the tank having a floor for supporting a weight of the liquid hydrocarbon. A filter is fitted to the floor of the tank. The filter is arranged to allow liquid water in the tank to drain out of the tank through the filter but substantially prevent the liquid hydrocarbon in the tank from doing so. The filter has a permeation member, such as a membrane, which is formed from a material such as graphene oxide which allows liquid water in the tank to drain out of the tank by permeating through the permeation member but substantially prevent the liquid hydrocarbon in the tank from doing so.